At present, edible pet chews produced from the prior art typically are made from rawhide and jerky, for example in the shape of a knotted bone, as described for example in U.S. Pat. No. 5,673,653. Such traditional knotted bone from rawhide, produced for the purpose of teeth grinding and chewing, has the disadvantages of mono-nutrition, excessively hard skin and poor palatability as well as environmental pollution, high cost and an insufficient source of raw materials.
U.S. Pat. No. 7,677,203, describes a knotted bone pet chew produced with plant starch as a main raw material for the outer casing. With plant starch as a main raw material, this chew has only the characteristics of dog feed and little or no teeth grinding and chewing functions.
U.S. Patent Application No. 2012/0234259 describes a knotted bone pet chew with a meat and rice based outer layer.